相关论文: Tuning the magnetism of ordered and disordered str…
Exact diagonalization calculations reveal that the energy spacing $\Delta$ in the conduction band tunes the interplay between the {\it local} Kondo and {\it non local} RKKY interactions, giving rise to a "Doniach phase diagram" for a…
Exact diagonalization results for Kondo nanoclusters alloyed with mixed valence impurities show that tuning the {\it energy spacing}, $\Delta$, drives the system from the Kondo to the RKKY regime. The interplay of $\Delta$ and disorder…
Recently there has been a resurgence of intense experimental and theoretical interest on the Kondo physics of nanoscopic and mesoscopic systems due to the possibility of making experiments in extremely small samples. We have carried out…
The quantum phase diagram of disordered electron systems as function of the concentration of magnetic impurities nm and the local exchange coupling J is studied in the dilute limit. We take into account the Anderson localisation of the…
The competition between the indirect exchange interaction (IEC) of magnetic impurities in metals and the Kondo effect gives rise to a rich quantum phase diagram, the Doniach Diagram. In disordered metals, both the Kondo temperature and the…
Ultrafast manipulations of magnetic phases are eliciting increasing attention from the scientific community, because potentially relevant to the understanding of nonequilibrium phase transitions and to novel technologies. Here, we focus on…
We study the tuning mechanisms of the Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange interaction between two lateral quantum dots in the Kondo regime. At zero magnetic field we observe the expected splitting of the Kondo resonance and…
When magnetic moments are immersed into the Fermi sea of itinerant electrons, rich quantum physics emerges. This is relevant for a wide range of materials including heavy Fermion systems, high temperature superconductors like the cuprates,…
Clusters containing a single magnetic impurity were investigated by scanning tunneling microscopy, spectroscopy, and ab initio electronic structure calculations. The Kondo temperature of a Co atom embedded in Cu clusters on Cu(111) exhibits…
The Doniach's diagram has been originally proposed to describe the competition between the local Kondo effect and the intersite RKKY interactions in cerium compounds. Here we discuss the extension of this diagram to different variations of…
Clusters of magnetic atoms lying on a metallic substrate can exhibit Kondo effect due to the exchange interaction with mobile electrons in the metal, which can be observed in STM measurements. The same interaction results in the induced…
The quasicrystal Al-Pd-Mn is a model system for an experimental study of the competition between Ruderman-Kittel-Kasuya-Yoshida (RKKY) and Kondo interactions. First, specific of such alloys, only a few Mn atoms carry an effective spin and…
We investigate Kondo correlations in a quantum dot with normal and superconducting electrodes, where a spin bias voltage is applied across the device and the local interaction $U$ is either attractive or repulsive. When the spin current is…
The interplay between the coupling of an interacting quantum dot to a conduction band and its connection to localized levels has been studied in a triple quantum dot arrangement. The electronic Dicke effect, resulting from quasi-resonant…
We propose a self-consistent approximate solution of the disordered Kondo-lattice model (KLM) to get the interconnected electronic and magnetic properties of 'local-moment' systems like diluted ferromagnetic semiconductors. Aiming at…
Several new aspects of the subtle interplay between electronic correlations and disorder are reviewed. First, the dynamical mean-field theory (DMFT)together with the geometrically averaged ("typical") local density of states is employed to…
We study the ground-state entanglement properties of nanostructured Kondo systems consisting of a pair of impurity spins coupled to a background of confined electrons. The competition between the RKKY-like coupling and the Kondo effect…
A theoretical concept is presented for the screening of several magnetic moments locally exchange coupled to conduction electrons in a metallic nanostructure. We consider a quantum confined multi-impurity Kondo model which exhibits the…
The delicate balance of spin-screening and spin-aligning interactions determines many of the peculiar properties of dilute magnetic systems. We study a surface-supported all-organic multi-impurity Kondo spin system at the atomic scale by…
Iron, cobalt and nickel are archetypal ferromagnetic metals. In bulk, electronic conduction in these materials takes place mainly through the $s$ and $p$ electrons, whereas the magnetic moments are mostly in the narrow $d$-electron bands,…